In reproducing the pedaling effects of an original piano performance, the piano playing mechanisms in player pianos have treated the pedals of the piano in one of two ways. The most widespread approach to pedaling has been to treat the pedals as "on-off" devices (commonly called "bang-bang" operation), and to provide brute force actuators for operating the pedal mechanisms. In order to reduce the pedal operating noise of the brute force actuators to an acceptable level and to insure that the actuation does not occur too quickly, devices such as dash pots have been used. The "bang-bang" operation, however, does not reproduce the pedaling movements in the reproduced performance which are proportional to those of the original performance. Indeed, the "bang-bang" operation results in an artificial, mechanical quality in many reproduced performances.
The second way in which piano playing mechanisms have treated the pedals in a reproducing piano is described and illustrated in my U.S. Pat. No. 4,450,749 issued May 29, 1984. That method and apparatus provides in the reproduced performance a very true reproduction of the pedaling effects in the original performance. During the original performance, the instantaneous position of the pedal mechanism (e.g. the actuator bar, or the damper lifter tray, depending upon the particular piano pedal) is sensed and recorded. At a later time when the performance is reproduced, the actuator positions the pedal mechanism in such a way that the dampers are positioned in substantially the same way they were positioned during the original performance. Such "position pedaling" gives excellent results, but a very high price, because such position pedaling requires a linear potentiometer and very accurate adjustments. The signal from such a linear potentiometer is precisely a function of the actual or achieved position of the pedaling mechanism itself. Such position pedaling, however, has really not lent itself to use in piano kits which are to be retrofitted into existing pianos. This is not only because of the high cost of the hardware, but because in the retrofitting field, the piano playing kits must be fitted into the pianos by technicians having a wide range of skills and tools. In particular, the design of the pedaling devices must be such that relatively unskilled workers can achieve acceptable results without special training or tools. Thus, in a piano retrofit kit, it is imperative to provide a robust, simple and inexpensive arrangement for pedaling. Heretofore, in such retrofit kits the only available approach to pedaling has been the "bang-bang" operation which gives the aforementioned artificial and mechanical quality to the reproduced performance.
The present invention is intended to remedy these defects by providing a robust, simple and inexpensive arrangement for pedaling which will closely approximate the quality of the pedaling effects heretofore only achievable by position pedaling as described in U.S. Pat. No. 4,450,749. The present invention is a vast improvement over the "bang-bang" operation, which heretofore has been the only pedaling approach which could be used in low-cost and retrofittable reproducing piano kits.